1. Field of the Invention
The present invention relates to a coordinate transformation device for electrical signal connection used for a probe card and the like, and more particularly to a coordinate transformation device for electrical signal connection to effectively provide wiring from contacts onto a probe card substrate.
2. Description of Prior Art
A probe card is used for circuit inspection of plural semiconductor chips formed on a wafer in the production process of an electronic device such as LSI. The probe card generally includes a mother board of a printed board that is provided with a common design independent of the type of semiconductor device; terminal pins that are arranged with a common design independent of the type of semiconductor device and are connected to a tester; probes arranged according to the type of the semiconductor device; and a child board of a printed board that is designed according to the type of semiconductor device to connect the probes with the terminal pins.
The child board has a function of transforming contact wiring of a narrow pitch into wiring of a rough pitch, and can be designed to be robust to measurement noise due to an appropriate shielding design. However, along with the increase of the integration of electronic devices, the number of circuit terminals (pads) on a semiconductor chip is increased and the pad pitch is narrowed. This leads to the necessity of further multi-layering of the child board and further reduction of the wiring, making the child board expensive to produce.
Meanwhile, the probe pin structure has requirements such as adaptation to the increasingly miniaturized pad arrangement and the narrowing of pitch, as well as precise control of behavior in the vicinity of the contact portion of the probe including the overdrive and scrub functions. In order to meet such requirements, the inventors have proposed improved technologies (for example, Patent Document 1: JP-A No. 274010/2004, and Patent Document 2: JP-A No. 300545/2005). These improved technologies propose a contact assembly formed by use of a resin film to which a copper foil as a metal foil is attached, etching the copper foil to form a conductive pattern of an electrical conductor including a probe function on the resin film, and laminating plural sheets of the resin film with the probe function. The contact assembly performs circuit inspection of semiconductor chips by bringing ends of the probes into contact with electrode pads of the semiconductor chips at a time.
The inventors have proposed a probe structure by film lamination. That is, as shown in FIG. 24 and other figures of Patent Document 1 and in FIG. 1 and other figures of Patent Document 2, a probe assembly is formed by attaching a copper foil plate to a surface of a ribbon-like (strip-like) resin film, forming a copper probe having a curved portion on the resin film surface by etching the copper foil plate, and laminating plural sheets of the resin film with the probe.
The inventors have also proposed a coordinate transformation device for electrical signal connection as a wiring method involved in the increased number of pads and the reduced pad pitch. The coordinate transformation device for electrical signal connection has a first wiring group and a second wiring group. The first wiring group is formed by use of a resin film to which a copper foil is attached, and etching the copper foil to form a conductive pattern on the resin film. The conductive pattern has input and output terminals protruding from the outer periphery of the resin film, in which the probe output terminal pitch is defined as the input terminal pitch, and the output terminal has a pitch larger than the input terminal pitch in a first horizontal direction (y direction). In the second wiring group, the output terminal pitch of the first wiring group is defined as the input terminal pitch, and the output terminal has a pitch larger than the input terminal pitch in a second horizontal direction (x direction) perpendicular to the first horizontal direction.
As an existing example, the above proposition will be described with reference to FIGS. 6A and 6B. FIG. 6A is a schematic assembly view of film-laminated type probes, which is an exploded perspective view showing a configuration of film-laminated type probes combined with a coordinate transformation device for electrical signal connection, including wiring to a mother board. FIG. 6B is a schematic front view showing a configuration of one film laminated type probe.
In FIG. 6B, a conductive portion 102 and enhanced conductive dummy portions 105 and so on are all formed by attaching a copper foil (e.g., beryllium copper) as a metal foil onto a resin film (e.g., polyimide resin) 101 and by etching the copper foil. Further, an insulating dummy portion 106 is formed by printing an insulating resin in a space between the conductive portion 102 and the enhanced conductive dummy portions 105 and so on. The resin film 101 has been provided with an opening 107 for inserting therethrough a support rod to fix plural resin films, which will be described below, and with a cut 108 for ensuring the probe movement. An end of the conductive portion 102, which is referred to as a probe end 103, comes into contact with a chip pad, and the other end thereof has a terminal 104 to be connected to a terminal of the coordinate transformation device for electrical signal connection described below.
FIG. 6A shows a general assembly view of the film laminated type probes having the function described above. More specifically, an LSI chip 109A has n pads 109p1-1 to 109p1-n on one side and n pads 109p2-1 to 109p2-n on the other side. In relation to the LSI chip 109A, a film-laminated type probe assembly 100A is formed by laminating film-laminated type probes 100a-1 to 100a-n and 100b-1 to 100b-n each corresponding to the pads arranged as described above, and by inserting support rods 110a, 110b into the laminated probes. Similarly, a film-laminated type probe assembly 100B is formed in relation to an LSI chip 109B, a film-laminated type probe assembly 100C is formed in relation to an LSI chip 109C, and a film-laminated type probe assembly 100D is formed in relation to an LSI chip 109D. The four film-laminated type probe assemblies are fixed together (not shown), and thus a probe assembly available for four chips is formed.
The figure also shows an example in which the probe assembly is connected to an inspection apparatus printed board 117 via a y-direction wiring group 111 and an x-direction wiring group 114. The y-direction wiring group 111 is formed by wiring conductors 113 on a resin film 112. The y-direction wiring group 111 has input portions 113 in that are arranged in line with a pitch Pa-in of plural signal line terminal portions 104 on one straight line selected in the film-laminated type probe assembly 100A. The input portions 113 in are formed so as to slightly protrude from the resin film 112. The pitch of the conductive patterns is extended in the y direction in a process to reach the output portions 113 out of the y-direction wiring group. Finally output terminals are formed to have a pitch Pa-out. The output portions 113 out of the y-direction wiring group are also formed so as to slightly protrude from the resin film 112.
Similarly, an x-direction wiring group 114 is formed by wiring conductors 116 on a resin film 115. The x-direction wiring group 114 has input portions 116 in that are arranged in line with a pitch Pb-in of the output portions 113 out of plural y-direction wiring groups on one straight line selected in the plural y-direction wiring groups 111. The input portions 116 in are formed so as to slightly protrude from the resin film 115. The pitch of the conductive patterns is extended in the x direction in a process to reach the output portions 116out of the x-direction wiring group. Finally output terminals are formed to have a pitch Pb-out matching the pitch of the input terminals 118in of the inspection apparatus printed board. The output portions 116 out of the x-direction wiring group are also formed so as to slightly protrude from the resin film 114.
The y-direction wiring groups 111 and x-direction wiring groups 114, which are formed as described above, are laminated and fixed, respectively. The film-laminated type probe assembly 100A and the y-direction wiring groups 111, the y-direction wiring groups 111 and the x-direction wiring groups 114, and the x-direction wiring groups 114 and the inspection apparatus printed board 117 are brought into contact at their input/output terminals which are formed so as to slightly protrude from the respective resin films, without being subjected to soldering. In this way, electrical continuity can be established. FIG. 7A shows a detailed view of the connection between the signal line terminal 104 of the probe and the input portion 113 in of the y-direction wiring group. FIG. 7B shows a detailed view of the connection between the output portion 113 out of the y-direction wiring group and the input portion 116 in of the x-direction wiring portion.
On the inspection printed board 117, each wiring is further guided from an input terminal 118 in of the inspection apparatus printed board to an output terminal 118 out thereof having a standard pitch Pc-out by a conductive pattern 118. The wiring is brought into contact with a pogo pin 119 of the inspection apparatus, and then an inspection is performed.
As described above, by combing the film-laminated type probe assembly and the wiring groups which are the coordinate transformation device, it is possible to gradually extend the high-density wirings in the vicinity of the high-density pads with narrow pitch, to the rough pitch of the input portions of the existing inspection apparatus board. Thus, it is possible to achieve a design suitable for the existing inspection apparatus board. In addition, the input terminal positions of the inspection apparatus board can be arbitrary designed, so that it is possible to realize a board having fewer layers than the existing multi-layer (several tens of layers) board. As a result, a low-cost probe device can be provided. Further, soldering is not necessary, so that the number of assembly man-hours is reduced and maintainability is improved.
However, in the conventional invention, after the film-laminated type probe assembly and the coordinate transformation device are laminated, the respective input/output terminals are connected by a spring force only in the z direction (pushing direction) held by each of the terminals, which has resulted in variation of the resistances of the terminals and occurrence of contact failure, or other problems.
The present invention is made to solve such problems, and is desirable to provide a low-cost probe device with high connection reliability capable of being applied to high density and arrow pitch pads, in which the electrical connection is ensured between the terminals of the film-laminated type probe assembly and the coordinate transformation device.